johnson



L. E. JOHNSON..

LIFTING JACK.

APPLICATION FlLED MAR. 23. 1918.

Patented May 27, 1919.

2 SHEETS-SHEET 2.

LawrencIJahwam b &guy

UNITED STATES PATENT OFFICE.

LAWRENCE E. JoHNsoN, or MELROSE, TMASSACHUSE'VJJTS, AssIGNoit 'ro MATTIE s.

I JOHNSON, or MELROSE, MASSAGHUSETTS.

LIFTING-JACK.

Speci fication of Letters Patenti Pateted May 27, 1919.

Application filed March 23, 1918. Serial No. 225376.

To all !whom it may concm: e

*Be it known that I, LAWRENGE E. JOHN- SON, a citizen of the United' States 'of America, and a resident of Melrose, in the county of Middlesex and Commonwealth of Massachusetts, have invented certain new and useul Improvements in Lifting-Jacks, of which' lateral shaft of the elevating mechanism` with 'gripping means which will normally rei tain the vertically moving member in any position to which it may be raised, butwhich may be manually released when it is' desired to lower said member, said grippng mechanism being associated with an actuai ting member which in its movement in one drawings'and to the claims hereinaftergiven. j

i v the presentinvention.

direction will increase the grip upon said shaft, while in its movement in the opposite direction the grip upon said shaft will be removed. p

The invention further consists in certain novel features of Construction and arrangement of parts which will be readily understood by reference to thedescription of the For the purpose of' illustrating the invention, one preferred' form thereof'is illustrated in thedrawings, this form having been found to give satisfactory and reliable results, although it is to be understoodthat i the various instrumentalitie's of which the p invention consists can be variously arranged and organized, and that the invention is not I v with the bevel gear. 16 as shown in the drawlimited to the precise `arra`ngementand organiz ation "of the instrumentalites as herein shown and described,-`except as required by the scope of the'appended claims;

Of the drawings H v i Figure 1 represents'a horizontal section of a lifting jack emb dying the principles of Fig. 2'represents a vertical section of same online 2, 25 on Fig; 1.

Fig. 3represents an enl arged-vertical sec-f tion of the lifting mechanism of said jack,

'the'cutting plane being on line 3, 3, on Fig. 2.

4 represents a vertical section on line i, 4, on F1g.` 2.

Fg. 5 repr'esents a vertical section on line 5, 5, on Fig. 3, and

Fig. 6 represents an elevation of the lateral shaft o fthe'lifting mechanism with the grip-ping mechanism therefor.

Similar characters designate like parts i throughout the several figures of the drawings.

In the drawings 10 is a stationary member provided with a base 11.

In the upper end of the stationary member 10 is positioned a non-revoluble nut 12 to which is threaded the screw 13 provided at its 'lower end with a shouldered nut 14: to'

limit the upward movement of said screw.

The upper end of said screw has keyed or otherwise Secured thereto a bevel gear '15 meshing with a bevel gear 16 forming a p part of the lifting mechanism.

The upper reduced end 23"of the screw 13 is adapted 'to freely revolve in the plate 21-which has supermposed thereon the closure 24 of a cylinder 25 the' lower end of which surrounds the stationary' member 10 and is movable vertically thereon; i i

From the' side of said cylinder '25 projects a' rectangular casing 26 having' a closing plate 27 having. bearings 28 and 29 therein to receive the lateral shafts 30 and 31 which are parallel to each other;

The shaft 30 is preferably 'formed integral ings and said bevel gear 16 haskeyed or otherwise secured 'thereto a spur gear 32 which 'meshes with an intermediate gear 32* The outer end of the sleeve 35 is chambered out 'as at '36 to inclose' the ratchet wheel 34 and in recesses 37 in said sleeve 35 are positioned pawls 38 movable about pivots 39 into engagement with the teeth of the ratchet wheel 34'.

Preferably three pawls 38 are used spaced equally about the aXis of the shaft 31 and at least one of which will, by its own weight be engaged with said ratchet wheel` 34 at all times.

The periphery of the. sleeve 35 is sur;

ping contact with the sleeve 35 thereby' pre- Venting the said sleeve turning about the aXis of the shaft 31.

The grip upon said sleeve 35 is suflicient'to prevent the lowering of the member 25 under the load supported. thereby until the grip upon said sleeve is released by the operator.

The releasing of the gripping of the member 40 is accomplished-by. the nanually operated member 41 extending through a slot 42 in thecasing 26 and threacled as at'43 to the closure 27..

The member 41 is provided' with a reduced shank 44 the end of which is adapted to be moved against the inner end of the member 40 and move said inner end suihciently to expand said member 40, thereby causing it to release its grip upon the' sleeve 35 and permit said sleeve to be rotate'd about the aXis of said shaft 31'. i'

In raising the movable member 25 the shaft 31 is rotated in 'the direction of'` the arrow a on Fig.. 3 of the drawings and by means of the pawl 38 the rotation of the ratchet wheel 34 relatively to' the sleeve 35 is limited to a movement in one direction only.

The movement of the` shaft in a reverse direction to that indicated by the arrow a is prevented as long as the member 40 remains in gripping contact with` the' sleeve 35, but as soon as the member 40' has been released from its grip upon thesleeve the shaft 31 may rotate in a reverse direction, carrying with it the sleeve 35, thus permitting the lowering of the movable member 25. The rapidity of the lowering may be regulated by the member 41, it being obvious that the rotation of the sleeve 35 will be retarded more or less depending on the degree of with a reduced end 47 to which is keyed a tube 48 surrounded by a helical gripping member 49, one end of which has formed therein an eye 50 through which extends' a pin 5-1 mounted in an actuating device 52.

This actuating device 52 is provided with a lateral projection 53, having a hole 54 ex tending therethrough adapted to receive the end of an Operating handle 55.

The inner end of' the handle 55 has an annular groove 56 therein, into which extends the end of a latch 57, pivoted at 58 to the projection 53. Between the opposite end: 59 of said latch 57 and said projection 53 is interposed a spring 60 tometain said latch in looking engagement with the handle 5-5.

By depressing the end 59 against the tenr sion of the spring 60 the latch 57' may be disengaged from the groove 5.6 thereby permitting the removal of said handle 55 from the hole 54 in said actuator 52..

When this change has beenmadethe shafl 31, and the gripping mechanism thereonwill, be actuated as before through` themedium; of the gears 32, 32 and 33.

lVhen it is desired to raise the movable member 25 the operator grasps, the. handle and depresses the same, t hereby increasing the grip on the tube 485, and causinga'movement contra-clockwise of the shaft 31 and' the ratchet 34 thereon.

In raising the handle the grip of the member 49 on the-tube 48 is released, and without moving the shaft 31, the actuator 52 is re,-

turned to its'nornal position preparatory'to another downward movementof said handle:

At each, downward stroke ofthe handle, 55rotary movement in' the direction of a'- row a, Fig. 3, is imparted to the shaft 31,.

and through the gears 33, 32 and 32 to the bevel gear 16, which in turn through .the bevcl gear 15, rotates the screw 13 in the stationary nut 12, and raises themember 25.,

The grip of the member40 on the sleeve 35 retains the movable member 25 in raised position until the operator releases the, grip by means of the member 41, and the load on the movablemember 25 will force'said member downwardly ata speed regulated by le ljustment of the positionof the mem- This makes a very effective brake for'lifting jacks, which is positive in action.

It is believed that the operation and` many advantages of the invention will -be, thoroughly understood without further de:

scription.

Having thus described my invention, I claim* i 1. The combination of an- Operating shaft; a sleeve loosely mounted on said shaft; means interposed between said sleeve and shaft limiti-ng the movement of said shaft relatively to said sleeve'to one direction only; a helical spring surrounding and normally gripping the periphery of said sleeve, said sprin having one end fastened and the other en free; and a member coacting with the free end of said spring and adjustable to release the gripping action of said spring.

2. The combination of an Operating shaft; a sleeve loosely monnted on said shaft; means interposed between said sleeve and shaft limiting the movement of said shaft relatively to said sleeve to one direction only; a helioal spring surrounding and normally gripping the periphery of said sleeve, said spring having one end fastened and the other end free; an adjustable member having an end adapted to bear against the free end of said spring and release its gripping 'action 'and means for limiting the movement of said member.

3. The combination of an Operating shaft; a sleeve loosely mounted on said shaft; means interposed between said sleeve and shaft limiting the movement of said shaft relatively to said sleeve to one direction only; 'a helical spring surrounding and normally gripping the periphery of said sleeve, said spring having one end fastened and the other end free; an adjustable member having an end adapted to bear against the free end of said spring and release its gripping action; and a collar on said member for limitinothe movement thereof.

4. The oombinaton of an Operating ally controlled devioe for releasing said' gripping means; a tube keyed to said shaft; a member surrounding and normally gripping said tube; and an aotuator for said shaft to which one end of said tube-gripping member is Secured.

5. The oombination of an Operating shaft; a sleeve loosely mounted on said shaft; means interposed between said sleeve and shaft limiting the movement of said shaft relatively to said sleeve to one direction only; means normally gripping said sleeveand preventing its rotation; a manually controlled device for releasing said gripping means; a tube keyed to said shaft'; a member surrounding and normally gripping said tube; an actuator for said shaft to which one end of said tube-grippng member is Secured; and a handle detaohably seeuredto said actuator.

Signed by me at 4; Post Office Square, Boston, Mass., this 20th day of March, 1918.

LAWRENCE E. JOHNSON.

Witnesses:

WALTER E. LOMBARD, NATHAN C. LOMBARD.

copies of this patent may be obtained for five cents each, by addressng the "Commissioner of Patents,

Washington, D. C." 

